Hydraulic vehicle lift



June 1934- L. c. STUKENBORG HYDRAULIC VEHICLE LIFT Filed Jan. 20, 1933Patented June .12, 1934 UNITED STATES PATENT OFFICE 1,962,220mmumovnmonn m'r Louis stukenborg, Memphis, Trm. Application January 20,1933, Serial No. 652,585

Claims. (01.138f-9) hicle, thus uselessly continuing the use of electricThis invention has general reference to hoisting or elevating devices inwhich there is employed a vertically-disposed cylinder, a hollow plungertherein which acts as a reservoir for the fluid used as a power medium,and a 'motor-.

driven pump for effecting the transfer of such' fluid from the plungerto the cylinder, the motor and plunger being carried by the plunger, andraised and lowered therewith. However, particular reference will be madehereinafter to the combination with such devices of means by which thecurrent-transmission cable will lead to the -motor in a way materiallydifferent from the leads known and employed heretofore, and to means forautomatically cutting off the currentconnection to the motor at apredetermined height of lift, so that, incidentally, the height of riseof the plunger may thus be automatically limited. f

In hydraulic lifts in which the motor is raised and lowered with theplunger, the provision of means for supplying current to the motoralways has involved numerous difficulties, particularly in vehicle liftsof the rotary type. In such lifts, the manner of use prohibits leadingthe cable to the motor from thereabove, or the provision of pits whereinthe cable may be received when the de- "vice is lowered, and thereforerequires that the cable be, led to the motor approximately at the levelof the surface in which the lift is installed, and that sufficientexcess cable be providedat or near the lifting device to allow for thelifting movement of the plunger. Such excess cable is subject tokinking, and to damage by the vehicle prior or subsequent to its beingraised, and is open to the further objection that it is likely to be intheway of anyone who may be working on the elevated vehicle. In effortsto avoid the foregoing objections, the makeshift has been adopted ofleading the cable along one of the rails that form part of the liftsuperstructure, and utilizing a slip or other type of coupling whichprovides for disconnection of the cable whenever electric current nolonger is required, such disconnection being necessary in order that thelift superstructure may be rotated, as well as for the purpose ofremoving the cable as an obstruction. The type of vehicle lifts hereinreferred to, ordinarily are equipped with some means whereby, when theliftsuperstructure has reached a predetermined height, further fluidpressure becomes ineffective; and it therefore has become commonpractice to permit the motor to continue in operation after completionof the raising operation, 55 and even during the servicing of the raisedvecurrent.

The present invention is intended to provide simple and efficient meanswhereby the foregoing and other objection may be obviated, and to thatend the primary object of the invention set forth herein is to improveupon the heretofore-known means of supplying electric current to themotors of vehicle lifts and the like, particularly in the followingrespects, it being intended that such improvements shall likewise beapplicable to hoisting or lifting devices other than those employed forraising vehicles:

First. By disclosing means whereby a powertransmission cable may be leadto a lifting or hoisting device in such manner that any slack insuchcable will be taken up automatically dur- -'cable.

Fourth. By disclosing means whereby lowering of the device willautomatically restore the power circuit to operative condition.

The means by which the foregoing and other objects are accomplished bymy present invention, and the manner of their accomplishment, readilywill be understandable from the following description on reference tothe accompanying drawing, in which- Fig. 1 is a sectional elevation of aportion of a vehicle lift having my improvements applied thereto.

Fig. 2 is a transverse sectional elevation, the section being takensubstantially on the line II-II of Fig. 1.

Fig. 3 is a diagrammatic view showing the power-transmission circuit andone arrangement of the cut-off switch.

' Referring now to the details of the drawing,

13A secured thereto, so as toconstitute what is commonly designated as afree-wheel type of lift table. Mounted in the upper end of the plunger11, is an electric motor 14, which is directly connected by a shaft 15with a pump 16 by which fluid is transferred from the plunger 11 to thecylinder 10. 17 is a release valve, which is manually operable to permitlowering movement of the plunger 11. The details of the foregoing parts,not being pertinent to the inven tion herein claimed, are notillustrated in the drawing. and will not be described herein in detail.7

Current to actuate the motor, is brought in from the usual power line 20through a hand-operated switch 21 from which circuit wires 22,preferably grouped in a cable 22A, lead to the motor 14. Preferably thecable is enclosed, to a point adjacent the cylinder 11 and verticallybelow the head 12, in a conduit 23. This conduit usually will leadbeneath the floor 24 and terminate as at 25 pointing vertically upward.From the conduit, the cable 22 is carried vertically upward to a groovedroller 26 over which it passes to a horizontally disposed roller 27, acomplementary roller 28 being preferably used in connection with theroller 26 to prevent accidental displacement of the cable. The cablepasses around the roller 27 and thence horizontally along the rail 13toward the free end of the rail. A bight is formed in the cable around aroller 29 and the cable lead back along the rail to the motor 14.

Preferably a cut off switch, generally indicated by the numeral 30, isinterposed in the cable line adjacent the head 12, which switchautomatically interrupts the circuit at a predetermined point,terminating the plunger rise.

The switch 30, includes poles 31 and a contact bar 32 normally held incontact therewith, as by a compression spring 33, to complete'thecircuit. The contact bar is disengaged to break the circuit by movementof the pulley shackle 34 against a head or button 35 connected to thebar. A spring 36 maintains tension on the pulley 29 to take up slack inthe cable. In use the hand switch 21 is closed to start the motor. Asthe lift rises, the cable 22A moves the pulley 29 toward the motor andswitch until at a predetermined height thepulley shackle 34 strikes thebutton 35 and disengages the contact bar from the poles, terminatingflow of current to the motor, and consequent rise of the plunger.

On completion of use the plunger is lowered in usual manner by use ofthe release valve 17. As the plunger lowers, the spring 36 automaticallytakes up the cable slack released by such lowering and incidental tosuch take up, restores the power circuit so far as the switch 30 isconcerned. Ordinarily the hand switch 21 has been opened also and suchaction does not restart the motor.

Should this have been overlok ed it is necessary to open the latterswitch, or greatly delay if not entirely stop the lowering of theplunger.

It will be seen that at all times, subsequent to, during, and after usethe cable 22A is so cared for as to afford the maximum availableprotection thereto and as to minimize its interference with access tothe lift or the vehicle thereon for servicing.

Ordinarily rotary movement of vehicle lifts is limited to acomparatively small arc of the complete circle and also occurs only inraised position. Under such circumstances that portion of the cableextending upward from the terminus 25, of the cable conduit, will wraparound the plunger without serious interference with such rotation ofthe lift, or damage to the cable.

Having described my invention, what I claim is:

1. In a device of the character described, comprising a cylinder, aplunger slidable therein, a motor carried by and movable withsaid'plunger, and a pump driven by said motor for imparting movement tosaid plunger, the combination, with a cable for supplying electriccurrent to said motor, of an automatic take-up for said cable, and aswitch through which said cable leads, said switch having meansco-operable with said takeup to open the switch when said plungerreaches a predetermined height.

. 2. In a device of the character described, comprising a cylinder, aplunger slidable therein, a support on said plunger, a motor carried byand movable with said plunger, and a pump driven by said motor forimparting movement to said plunger, the combination, with a cable forsupplying electric current to said motor, the lead of said cable beingsuch as to form a bight therein on said support, of a pulley in saidbight, a switch through which said cable leads, means for moving saidpulley to take up slack in said cable during raising and loweringoperations of said plunger, and means for throwing said switch bymovement of said pulley.

3. In a vehicle lift, including a vertically disposed cylinder, aplunger slidable therein, a head secured to said plunger, a pair ofvehicle-supporting rails secured to said head and extendinglongitudinally therefrom, a motor carried by said plunger and meansdriven by said motor for sliding said plunger; the combination with aconduit terminating adjacent said cylinder in a vertically disposedportion, a pulley journalled on said head above the end of said conduit,a laterally disposed pulley journalled on one of said rails, a movablepulley-shackle disposed against said rail between said head and the endof said rail, a pulley journalled in said shackle, and a tension springhaving one end secured adjacent the end of said rail and the other endsecured to said shackle, I

of a cable for supplying current to said motor, disposed in said conduitand extending vertically upward therefrom, to and over said head-pulley,said rail-journalled pulley and said movable pulley and leading from thelatter back along said rail to said motor, whereby tension of saidspring on said cable will prevent the formation of slack in said cableduring movement of said plunger.-

ley journalled in said shackle, and a tension spring having one endsecured adjacent the end of said rail and the other end secured to saidshackle, of a cable for supplying current to said motor extendingvertically upward adjacent said cylinder, said cable leading to and oversaid headpulley, to said rail-joumalled pulley and said movable pulleyand leading from the latter back along said rail to said motor, wherebyon upward and downward movement of said plunger said spring willlengthen and retract to pay out and take up slack in said cable.

5. In a vehicle lift, including a vertically disposed cylinder, aplunger slidable therein, vehicle supporting means, including a pair ofvehiclesupporting rails, secured to said plunger, said rails extendinglongitudinally therefrom, a motor carried by said plunger and meansdriven by said motor for sliding said plunger; the combina tion with apulley journalled on said means, a pulley, disposed laterally from saidfirst pulley, joumalled on one of said rails, a 'reciprocablepulley-shackle disposed against said rail between said plunger and theend of said rail, a pulley journalled in said shackle, and a tensionspring having one end secured adjacent the end 01 said rail and theother end secured to said shackle, of a cable for supplying current tosaid motor extending vertically upward adjacent said cylinder, saidcable leading to and around said pulleys, and leading from saidshackle-carried pulley along said rail to said motor, whereby on upwardand downward movement of said plunger said springwill lengthen andretract to pay out and take up slack in said cable.

LOUIS C. BTUKENBORG.

